Fluorine-containing blocked isocyanates

• US 20020123642A1
• Filed: 09/14/2001
• Published: 09/05/2002
• Est. Priority Date: 09/20/2000
• Status: Active Grant

• Current Assignee: Bayer AG
• Original Assignee: Bayer AG
• Inventors: Baumbach, Beate, Gonzalez-Blanco, Juan, Fussel, Christian, Koenig, Eberhard
• Granted Patent: US 6,509,433 B2
• Time in Patent Office: Days
• US Class Current: 560/25
• CPC Class Codes: C08G 18/8074 Lactams
• CPC Class Codes: C08G 18/8087 containing halogen atoms
• CPC Class Codes: C08G 2150/20 Compositions for powder coatings
• CPC Class Codes: C09D 175/04 Polyurethanes

Abstract

The present invention relates to blocked fluorine-containing polyisocyanates which have a fluorine content, calculated as F=19, of 1.0 to 20.0 wt.%, preferably 4.0 to 10.0 wt.%, and are suitable for preparing stoving coatings having a water- and soil-repellent surface, wherein the fluorine-containing polyisocyanates are based on the reaction product of aliphatic polyisocyanates or polyisocyanate mixtures having an NCO content of 10 to 25 wt.% and a functionality of at least 2.5 with monofunctional isocyanate blocking agents and a fluorinated monoalcohols wherein

i) 75 to 95 equivalent-% of the isocyanate groups are reacted with isocyanate blocking agents,

ii) 5 to 25 equivalent-% of the isocyanate groups are reacted with fluorinated monoalcohols and

iii) the equivalents of i) and ii) add up to 100%.

The present invention also relates to a process for the preparation of these blocked fluorine-containing polyisocyanates and to their use as crosslinking agents in the preparation of polyurethane plastics, especially polyurethane coatings.

Claims

1. A blocked fluorine-containing polyisocyanate which has a fluorine content, calculated as F=19, of 1.0 to 20.0 wt. % and is suitable for preparing stoving coatings having a water- and soil-repellent surface, wherein the fluorine-containing polyisocyanate is based on the reaction product of an aliphatic polyisocyanate or polyisocyanate mixture having an NCO content of 10 to 25 wt. % and a functionality of at least 2.5 with a monofunctional isocyanate blocking agent and a fluorinated monoalcohol wherein

i) 75 to 95 equivalent-% of the isocyanate groups are reacted with an isocyanate blocking agent,

ii) 5 to 25 equivalent-% of the isocyanate groups are reacted with a fluorinated monoalcohol and

iii) the equivalents of i) and ii) add up to 100%.

2. The blocked fluorine-containing polyisocyanate of claim 1 wherein the blocked fluorine-containing polyisocyanate has a fluorine content, calculated as F=19, of 4.0 to 10.0 wt. %.

3. The blocked fluorine-containing polyisocyanate of claim 1 wherein the fluorinated monoalcohol comprises the addition product of perfluoroethyl iodide, perfluorobutyl iodide or perfluorohexyl iodide onto allyl alcohol with subsequent hydro-deiodination to give the corresponding fluorinated alcohol.

4. The blocked fluorine-containing polyisocyanate of claim 2 wherein the fluorinated monoalcohol comprises the addition product of perfluoroethyl iodide, perfluorobutyl iodide or perfluorohexyl iodide onto allyl alcohol with subsequent hydro-deiodination to give the corresponding fluorinated alcohol.

6. A polyurethane plastic prepared from the blocked fluorine containing polyisocyanate of claim 1 and an isocyanate-reactive component.

7. A polyurethane coating composition containing the blocked fluorine-containing polyisocyanate of claim 1 and a e preparation of binders for polyurethane lacquers.

8. A coated substrate prepared from the polyurethane coating composition of claim 7.

9. The coated substrate of claim 8 wherein the substrate is metal.

5. A process for the preparation of a blocked fluorine-containing polyisocyanate which comprises initially introducing an aliphatic polyisocyanate or polyisocyanate mixture, optionally in a solvent, into a reaction vessel at a temperature of 50 to 70°

C. with stirring, subsequently adding a fluorinated monoalcohol, reacting the mixture at 80 to 110°

C. until the calculated NCO content is reached and then reacting the remaining NCO groups with a corresponding amount of blocking agent at 70 to 110 °

C.